Ishikawa Prefecture's Pride – XL Grapes with Intense Flavor Thanks to Extraordinary Sugar Concentration. A Single Grape Could Cost Up to €400: History, Characteristics, and Evolution of the Ruby Roman Variety.
The product
The Japanese people's love for exceptional foods, treated and valued as luxury goods, is well-known. However, not everyone might be aware that, after Kobe beef, square watermelons, Sekai apples, and Bijin-hime strawberries, another luxury product from the Land of the Rising Sun emerges – Ruby Roman, the world's most expensive table grape variety. In 2020, during a dedicated auction, a 900-gram bunch of Ruby Roman grapes fetched over $10,000. It naturally raises the question: why can a grape variety be so expensive?
Firstly, Ruby Roman exclusively grows in the Ishikawa Prefecture, in the Chūbu region of Japan, precisely on the Honshū Island. Its cultivation began in the spring of 1995 at the Sand Dunes Agricultural Research Center, where 400 seeds collected from large black grapes called Fuji Minoru were planted in a test plot to satisfy grape growers' desires. The young plants began to flourish around 1997, with only four of the 400 specimens producing fruit, and Ruby Roman is one of them. However, it wasn't until 2008 that it entered the market, and its success was instant, with prices quickly "maturing."
The criteria for classifying a grape as Ruby Roman are extremely strict: each grape must weigh at least 20 grams, have a minimum diameter of 30 millimeters, and possess a sugar content of 18%. There is even a premium class of Ruby Roman with berries that exceed 30 grams. Before being put on the market, the latter are inspected one by one, and once they pass the checks, each package is affixed with a certification of authenticity. Ruby Roman clusters exhibit a vibrant ruby-red color and astonishing sweetness, making the berries resemble genuine precious stones.
Ruby Roman is cultivated inside greenhouses, where, in addition to size, hue, and sugar level, great attention is paid to three other parameters: the intensity of light (crucial for color development – insufficient light results in pale white grapes), temperature control through window adjustments to ensure air circulation, and rigorous cultivation methods – both manual and mechanical. All this care is aimed at ensuring the production of clusters with uniform and identical grapes. The aesthetics of food are indeed a fundamental aspect of Japanese gastronomic culture. The residents of Ishikawa are so proud of this fruit that the name "Ruby Roman" was chosen through a public referendum.
